Wire screens are used for chemical filtration, architectural accents, downhole tools (e.g., gravel pack screens), and other purposes. FIG. 1 shows the typical construction of a prior art wire screen 10. As shown, the wire screen 10 typically has parallel wires 12 attached by welds 16 to parallel rods 14 oriented perpendicularly thereto. The wires 12 can be V-shaped wires, and the rods 14 can be cylindrical in cross-section as shown, but can also be square, rectangular, etc.
Both the wires 12 and rods 14 are typically made of stainless steel, but they can be made of other materials, including aluminum and copper alloys. In general, attachment of the wires 12 to the rods 14 can be performed by electric resistance welding, binding, or other technique. The wires 12 and rods 14 can be formed in to a screen 10 having a flat shape, a cylindrical shape, or a conical shape in which the screen's diameter gradually changes continuously along the length of the screen. In any of these types of screens, the rods 14 have edges that are linear or straight. In the flat shaped screen, the rods 14 arrange so that their edges lie in a plane. In the cylindrical shape, the rods arrange to form straight sidewalls. In the conical shape, the rods 14 have linear edges and are angled inward toward each other.
In architectural applications, wire screens 10 can be used on a building as a decorative feature for decorative lighting towers, frontages, overhangs, column covers, floor gratings, ventilation grids, wall partitions, handrails, etc. For example, the Seven World Trade Center in New York and the Guthrie Theater parking garage in Minneapolis have wire screens that cover the exterior. Typically, the architectural design of such wire screens focuses on the reflectivity and orientation of the wire surfaces to enhance appearance.
In industrial applications, gaps between the screen's wires 12 can filter chemical compositions, solids, and other media. For example, radial flow assemblies are used in chemical processes such as catalytic reforming, styrene dehydrogenation, ammonia conversion, and the like. In its simplest form, a radial flow assembly has two concentric screens with the annulus filled with treatment media. FIG. 2 shows an example of a typical radial flow reactor vessel 20 for a chemical processing system. The vessel 20 includes a chamber 22 having an outer basket 30 and a centerpipe 40, although a variety of other configurations are known and used.
Both the basket 30 and centerpipe 40 are cylindrical and are composed of wires welded to rods (such as wires 12 and rods shown above in FIG. 1) to form a number of slot openings for filtering the radial process flow. The slot openings on either one or both the centerpipe 40 and outer basket 30 can be oriented vertically to allow media to slide up and down during processing without becoming abraded by edges of the openings. Alternatively, the slot openings can be oriented horizontally along the length of the centerpipe 40 and/or basket 30. Depending on the implementation, the basket 30 and centerpipe 40 may be any height and diameter, and the slot openings between the wires can be as small as 0.010 in. (0.25 mm) and can be increased by to 0.0004 in. (0.01 mm) increments to practically any desired width.